(a) Field of the Invention
The present invention relates to positive displacement pumps or motors and, more particularly, to rotary actuated pumps and motors. More specifically, the present invention relates to a rotary pump or motor having a single rotary element designed to form fluid displacement chambers as well as to serve as a rotary valve control.
(b) Description of the Prior Art
Rotary motors or engines having rotary piston members are well known in the ar. Examples of such known devices are illustrated in U.S. Pat. Nos. 659,675; 676,897; 686,8O9 and 1,114,132. Motors and pump devices wherein a rotor having cam surfaces is involved in the displacement of fluid are illustrated in U.S. Pat. Nos. 205,868; 2,896,590; 3,129,669; 3,319,615; 3,525,216 and 4,605,361. However, in each of these prior art embodiments, multiple rotating elements are utilized, often with complex camming arrangements. These complex devices result in multiple wearing surfaces which increase the cost of maintenance. They also require complex mechanical interaction which require complicated timing arrangements and other related complications. The cost of original construction is also high for such complex devices. Moreover, in most of these devices, the camming rotor is not utilized for the purpose of directly forming fluid displacement chambers. Consequently, there is no currently known positive displacement pump or motor which is simple in design and construction, capable of small size construction, limited in mechanical complexity, and yet large in flow rate or displacement relative to its size.